whats the big dif can someone tell me

I WOULDnt waste my money on hydros unless you are having problems with the cable set up. if it aint broke dont fix it. they are much smoother and a better feel if you are doing stunts and using the back brake. cable brakes is more like on or off. hydrolic has some play in there
 
To convert to hydros you still need to fabricate and weld a tab for resorvoir,bracket for master cylinder,and extend the stock pedal.Not real hard but does take some time and equipment.If you do it let me know I will show you what I did.
 
Have you considered buying the shorty brake cable? I bought that for my son's Blaster, and it works great for our purposes.. He can lock the rears up at will now... They are not as good as hydraulics, but they work great for like $30.